Windows 7 License: Upgrade vs. Full
If you're considering the purchase of a Windows 7 Operating System, there are several things you need to keep in mind. Most importantly is the difference between an "Upgrade license" and a "Full license":
- Windows 7 Upgrade license allows you to upgrade your existing Operating System only if your PC is currently licensed for Windows XP or Vista. If your PC is not licensed for Windows XP or Vista, you'll need to buy a Full license.
- Windows 7 Full license allows you to install Windows 7 on any PC with or without an existing Operating System. For example, if you have a PC with no Operating System or an Operating System other than Windows XP or Vista, you'll need a Full license.
* All editions of Windows XP and Windows Vista qualify you to upgrade. So, if you're running either on your PC today, buy a package labeled "Upgrade".
To Upgrade, run Windows 7 Upgrade Advisor to make sure your PC can run Windows 7 and then review the Upgrade Advisor information prior to buying or installing Windows 7 on your PC.

